[BugFix]Qwen-Image performance regression by using omni RMSNorm(RMSNorm backend) (#3933)

Signed-off-by: NumberWan <wantszkin2003@gmail.com>

vllm_omni/diffusion/models/qwen_image/qwen_image_transformer.py

@@ -17,7 +17,6 @@ from diffusers.models.embeddings import TimestepEmbedding, Timesteps
 from diffusers.models.modeling_outputs import Transformer2DModelOutput
 from diffusers.models.normalization import AdaLayerNormContinuous
 from vllm.logger import init_logger
-from vllm.model_executor.layers.layernorm import RMSNorm
 from vllm.model_executor.layers.linear import (
     ColumnParallelLinear,
     QKVParallelLinear,
@@ -44,6 +43,7 @@ from vllm_omni.diffusion.distributed.sp_plan import (
 )
 from vllm_omni.diffusion.forward_context import get_forward_context
 from vllm_omni.diffusion.layers.adalayernorm import AdaLayerNorm
+from vllm_omni.diffusion.layers.norm import RMSNorm
 from vllm_omni.diffusion.layers.rope import RotaryEmbedding
 
 logger = init_logger(__name__)